21.5. Expressions

Expressions
are used in @, if, and
while statements to perform arithmetic, string
comparisons, file testing, and so on. exit and
set also specify expressions, as can the
tcsh built-in command
filetest. Expressions are formed by combining
variables and constants with operators that resemble those in the C
programming language. Operator precedence is the same as in C but can
be remembered as follows: